PRENDEN Germany (Reuters) - Hidden away in a forest near Berlin lies a huge abandoned Cold War-era bunker, built to withstand a nuclear attack, that enthusiasts hope can become a new magnet for tourists visiting the former East Germany.
The 7,750-square meter (83,000 sq feet), three-storey structure is known as 'Honecker's Bunker' after Communist leader Erich Honecker, whom it was built to protect in the event of a nuclear war between the Soviet bloc and the West.
Now, as Germans mark the 25th anniversary of the fall of the Berlin Wall and the beginning of the end of East Germany, some Berliners are looking to turn the bunker into a museum, tapping into a wave of nostalgia - or 'Ostalgie', from the German word 'Osten' for East - for the communist past.
"When you get inside and you know what it was for, or what they planned to withstand or what they were afraid of, you really get a feeling of how seriously worried they were," said Hannes Hensel, leader of the efforts to reopen the bunker.
The site, located about 50 km (30 miles) northeast of Berlin and built to accommodate up to 400 of the Communist Party's political and military leadership, was abandoned and shut after the end of the Cold War.
Hensel helped to get it re-opened to the public for a brief three-month period in 2008 when it drew some 20,000 visitors.
A similar bunker built near Bonn to protect West German leaders has stayed open since 2008 and attracts about 80,000 visitors every year.
Hensel is looking for investors to raise an estimated 1.5 million euros ($1.86 million) to open the museum. He hopes to organise tours and perhaps also to open a restaurant and hotel at the site.
'Honecker's Bunker' was one of the most advanced of its kind in the Soviet bloc. Built between 1978 and 1983 with 85,000 tonnes of reinforced concrete, it was made to withstand chemical attacks as well as a 1-megaton atomic bomb - roughly 80 times more powerful than the one dropped on Hiroshima in 1945.
"It is one of the most important buildings of the time," said Holger Happel of the research and tour group Berlin Unterwelten.
"While other east European countries had already started changing their political system step-by-step (in the 1980s), the East German government still clung to their communist ideals and spent big money on border protection, bunkers and military facilities," he said.
If Western forces had attacked, members of East Germany's National Defence Council would have retreated into the bunker after first being rinsed of any radioactive or chemical materials in a decontamination chamber.
They could have completely and independently sustained themselves there for two weeks, using the bunker's own waterworks, power system, air conditioning and food supplies.
After two weeks, they would assume conditions outside were safer and escape to a better location in armoured vehicles.
Honecker himself, who died in 1994 after going into exile in Chile, only visited the bunker once. And it remained completely unknown to most East Germans, even those sent to guard it.
"The 300 soldiers who patrolled the area did not know what was there," said Hensel. "They only knew they were guarding something important, but not what it was."
The privileged few holed up in the bunker would have been separated from their families, its former technical director recalled.
"For us it was a very emotional time because we worked at a bunker and knew that our families were at home and if an armed conflict broke out, then they would be defenceless," Juergen Freitag told Reuters.
"It was, of course, a horrible feeling to have."
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Editing by Gareth Jones and Mark Trevelyan